The proposed research will deal with two studies of the behavioral effects of the estrogen inhibitor clomiphene citrate. The first study will examine the effects of prenatally administered clomiphene on the development and adult manifestation of sexual behavior. Pregnant female rats will be treated on days 13-20 of pregnancy with clomiphene citrate, estradiol benzoate, of an inert vehicle. The offspring will be observed during their development for normal or abnormal sexual behaviors. It is expected that the results obtained will be comparable to other experiments involving prenatal hormone treatment and sexual differentiation. The second study will be quite similar to the first except that clomiphene will be administered for the first five days post partum. Again, the results are expected to be comparable to those obtained from studies of perinatal hormone treatment relating to sexual differentiation. The two studies will give insight into the mechanisms of sexual development and differentiation and may serve to illuminate the action of clomiphene since other research involving hormone inhibitors administered perinatally has proven quite fruitful. The use of a powerful statistical design will permit unusual comparisons to be made within the data from both experiments.